k8s_deployment_hpa.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: nginx
spec:
  # this value goes away - we don't need to explicitly set the number of replicas anymore!
  # replicas: 3 
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:stable-alpine
        ports:
        - containerPort: 80
        resources:
          # You need to specify the metric the HPA object will reference
          limits:
            cpu: 200m
            memory: 500Mi
          requests:
            cpu: 100m
            memory: 200Mi